1. Field of the Invention
The present invention relates to a radiographic image capturing apparatus, a radiographic image capturing system, and a method of supplying electric power to a radiographic image capturing apparatus. More particularly, the present invention concerns a radiographic image capturing apparatus preferably for use as a portable radiographic image capturing apparatus, which can be carried outdoors by an operator, a radiographic image capturing system, and a method of supplying electric power to a radiographic image capturing apparatus.
2. Description of the Related Art
In the medical field, there have widely been used radiographic image capturing apparatus, which apply radiation to a subject and guide radiation that has passed through the subject to a radiation conversion panel (radiation detector), which captures a radiographic image from such radiation. Known forms of radiation conversion panels include conventional radiation film for recording a radiographic image by way of exposure, and stimulable phosphor panels for storing radiation energy representing a radiographic image in a phosphor, and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. Radiation film with the recorded radiographic image is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image.
In an operating room or the like, for the purpose of quickly and appropriately treating patients, it is necessary to read a recorded radiographic image immediately from a radiation conversion panel after the radiographic image has been captured. As a radiation detector which meets such a requirement, there have been developed a radiation detector of a direct conversion type (electronic cassette) having a solid-state detector for converting radiation directly into electric signals, and a radiation detector of an indirect conversion type (electronic cassette) having a scintillator for temporarily converting radiation into visible light and a solid-state detector for converting such visible light into electric signals (see U.S. Pat. No. 5,514,873).
Such radiographic image capturing apparatus are developed on the assumption that they will be used to capture radiographic images of patients in medical organizations.
There are potential demands for capturing radiographic images outside of medical organizations. To meet such demands, radiographic image capturing apparatus, which are mounted on motor vehicles used to perform medical checkups, have been proposed in the art. However, such proposed radiographic image capturing apparatus, which are disposed on medical checkup motor vehicles, are relatively large in size. Needs have arisen for capturing radiographic images of persons who suffer from natural disasters at disaster sites, or persons who are receiving home-care services at their homes. However, existing medical checkup motor vehicles cannot be used in the former applications, since it is difficult to get to disaster sites. Although existing medical checkup motor vehicles may be driven to the homes of persons who are receiving home-care services, the image capturing process is highly burdensome to people to be imaged, because they have to be taken from their homes into the medical checkup motor vehicle in order to capture radiographic images of such people. Therefore, there have been demands for small-size portable radiographic image capturing apparatus for use at natural disaster sites or at homes receiving home-care services.
There has been developed a portable radiographic image capturing apparatus, which can be folded into a compact form in its entirety (see Japanese Laid-Open Patent Publication No. 2007-530979 (PCT)). In addition, radiation sources comprising field-electron-emission-type electron sources based on carbon nanotube (CNT) technology have also been developed (see Japanese Laid-Open Patent Publication No. 2007-103016, and AIST: Press Release, “Development of Portable X-ray Sources Using Carbon Nanostructures” [online], Mar. 19, 2009, National Institute of Advanced Industrial Science and Technology, Internet <URL:http://www.aist.go.jp/aistj/press_release/pr2009/pr20090319/pr20090319.html> (hereinafter referred to as “Document 1”). It is expected that small-size, lightweight radiographic image capturing apparatus including radiation sources will become available in the art. Further, a portable size and high energy X-ray source was developed by using LiTaO3 that is a typical pyroelectric crystal (see “Applying Pyroelectric Crystal to Small High Energy X-Ray Source”, Advances in X-Ray Chemical Analysis, Japan, 41, 2010, pages 195-200 (hereinafter referred to as “Document 2”)).
Wireless electric power transmitting schemes are known from IEDM Plenary Talk, “Arrival of Contactless Power Transmission Sheet Expected to be Embedded in Walls and Floors, developed by the University of Tokyo” [online], Dec. 4, 2006, Internet <URL:http://techon.nikkeibp.co.jp/article/NEWS/20061204/124943/> (hereinafter referred to as “Document 3”), and Nikkei Electronics, “Development of Wireless Power Transmission Technology, a 60-W Lamp Turned on in Experiment,” Dec. 3, 2007, pages 117-128 (hereinafter referred to as “Document 4”). The process disclosed in Document 3 transmits electric power based on electromagnetic induction from a primary coil embedded in a contactless power transmission sheet. The process disclosed in Document 4 is a wireless power transmission technology based on magnetic field resonance between two LC resonators.
If a small-size radiation source can be reduced in size as disclosed in Japanese Laid-Open Patent Publication No. 2007-530979 (PCT), Japanese Laid-Open Patent Publication No. 2007-103016, Document 1, and Document 2, then the radiation source may be combined with an electronic cassette as disclosed in U.S. Pat. No. 5,514,873 in order to reduce the size and weight of the radiographic image capturing apparatus, which includes a radiation source and an electronic cassette, thereby allowing the radiographic image capturing apparatus to be moved with ease. In other words, a portable radiographic image capturing apparatus can be realized.
However, since such a portable radiographic image capturing apparatus mainly is used outdoors, a problem arises as to the availability of a power supply therefor. One solution would be to carry separate batteries together with the portable radiographic image capturing apparatus. More specifically, it is necessary to prepare a battery dedicated for the radiation source, a battery dedicated for the electronic cassette, and a battery dedicated for a controller (personal computer), etc., for use with the portable radiographic image capturing apparatus. In addition to such batteries, backup batteries also need to be carried, in case images have to be recaptured or additional images have to be captured. As a result, the entire radiographic image capturing system to be carried around is liable to be of an increased size and weight, thus reducing the ease (including portability) with which the radiographic image capturing system can be used.